1. Field of the Invention
The present invention relates to a technique for imaging of a sample plate which comprises a plurality of wells which contain a fluid or the like. The term “fluid or the like” used herein is a general term for liquids, gel-like or semi-fluid solid bodies and substances which are introduced into the wells as they are fluid and which thereafter harden.
2. Description of the Related Art
In medical or life science experiments, a fluid or the like (e.g., a culture fluid) is for example poured into each one of many depressed parts called wells which are arranged in a plate-like device, and cells or the like cultured in the fluid or the like are observed. Such a device is called, for example, a microplate or a microtiter plate. For example, in the process of developing an anticancer drug, a multitude of samples obtained by causing various drugs to act on cells at different densities are observed and the life and death of the cells are judged. Various optical devices for supporting such observations have been conventionally proposed.
For example, in an optical apparatus disclosed in the description of U.S. Pat. No. 7,718,131, wells are imaged by irradiating light from above the wells and receiving light transmitted to a lower side. In this technology, an image of one well is reformed from a plurality of partial images imaged while light is irradiated in different manners to cope with a problem that the shadow of a side wall surface of the well is reflected on an image due to the incidence of light focused by a lens.
Since it takes time to perform imaging of one well according to the conventional technique mentioned above, long time is necessary to obtain an image of an entire plate which comprises a number of wells. Over the recent years in particular, a plate with a hundred or more wells has been put into use, and it has become necessary to perform imaging of these many wells at a high measurement accuracy and at a high speed. However, the conventional technique mentioned above cannot meet the requirement sufficiently.